One of the more prolific Golden Age companies, many of these characters turned
up again in Alan Moore's Tom Strong (thanks to Mike Murphy for this information).
As Joshua Geren, another contributor, notes "These heroes are considered
to be a "public domain" under US laws in that there is no current copyright
holder, and thusly, the same characters, or versions therof, have appeared
in various publications, among them, recently, the notable Alan Moore effort
"Terra Obscura" from ABC Comics." Some of them (Doc Strange, Fighting Yank)
also turned up briefly in Americomics in the 1980's, before being killed
off in Femforce #43, and many subsequently saw revivals both in Image's Savage
Dragon and as part of Project Superpowers.